A number of today's highly integrated, multi-layer circuit boards with fine pitch integrated circuits are virtually impossible to access physically for testing. Some traditional testing methods, such as functional test, only access a board's primary I/Os (input/outputs), thereby providing limited coverage and poor diagnostics for board network faults. Other traditional testing methods, such as in-circuit testing, involve physically accessing each wire on the board via “bed of nails” probes and testers, and may be expensive to implement. To alleviate the growing costs of designing and producing digital systems, boundary scan was developed as a way to test interconnects (i.e., thin wire lines) on a printed circuit board without using physical probes. However, along with providing functional and interconnect testing capabilities, boundary scan may also be utilized to provide built-in self test procedures. Boundary scan has basically transformed a number of extremely difficult PCB (printed circuit board) testing problems into problems that can be dealt with via software control.
Boundary scan provides the above-referenced capabilities by providing an interface into embedded digital electronics. Boundary scan may be utilized to provide various functions, such as board test, chip test, and system debug functions. However, with current implementations of boundary scan, such functions require extensive access to hardware and software throughout a system, thereby making it difficult to ensure protection of critical or sensitive information from unwarranted access.
Therefore, it may be desirable to have a system and method for providing secure boundary scan interface access which addresses the above-referenced problems and limitations of the current solutions.